John R. Clem: Contributions to the Phenomenology of Superconductivity

John Clem, Distinguished Professor of Physics at Iowa State University and Ames Laboratory, who passed away in August 2013, was for many decades one of the world's leading contributors to the phenomenology of superconductivity. Hisfundamental contributions included elucidating domain structures in Type I superconductors, modeling reversiblemagnetization and upper critical field of high temperature superconductors (HTS), introducing the concept of“pancake” vortices in highly anisotropic HTS materials, and developing the theory of flux cutting. He alsotook a great interest in applied superconductivity and consulted for organizations such as IBM, Pirelli Cables and AMSC,deriving the microwave properties of HTS films, elucidating the mechanism of current flow in first generation HTS wires,establishing the transport measurement of ac loss in tapes, and calculating ac loss of fault current limiter coils andHTS power cables. As founder and chief editor of High-Tc Update, he also provided much needed perspective on the torrentof developments during the early years of HTS discoveries.